Groove tip impression is deformation of the prism tips (i.e. apexes) of prismatic microstructures of a brightness enhancement film. U.S. Pat. No. 5,626,800 describes methods of producing a microstructure bearing article such as a brightness enhancing films. Also described is a groove tip penetration test having good correlation to visible groove tip impressions. However, since the groove tip penetration test described in U.S. Pat. No. 5,626,800 requires the use of special equipment to measure the penetration of steel balls into a brightness enhancement film, industry would find advantage in alternative methods of determining resistance to groove tip impression.